Development of EST-SSR markers for genetic diversity analysis in coconut (Cocos nucifera L.)

Molecular Biology Reports - Genetic improvement in coconut relies on exploiting the vast existing diversity among coconut accessions. Robust molecular markers are a pre-requisite for efficient...     

Calcium ionophore-induced egg activation and apoptosis are associated with the generation of intracellular hydrogen peroxide

The present study was designed to investigate whether calcium ionophore-induced activation and apoptosis are associated with the generation of hydrogen peroxide (H₂O₂) in rat eggs cultured in vitro. Culture of metaphase-II (M-II) arrested eggs in Ca²⁺/Mg²⁺-deficient medium did not induce egg activation, while a second polar body was observed in 20% of eggs when cultured in Ca²⁺/Mg²⁺-supplemented medium. In Ca²⁺/Mg²⁺-deficient medium, lower concentrations of calcium ionophore (0.2,0.4 and 0.8 µm) not only induced egg activation in a dose-dependent manner but also generation of intracellular H₂O₂ (84.40±0.50 ng/egg) when compared to control eggs (80.46±1.34 ng/egg). The higher concentration of calcium ionophore (1.6 µm) induced apoptosis and pronounced generation of intracellular H₂O₂ (92.43±0.93 ng/egg) in treated eggs. Conversely, cell-permeant antioxidant such as 2(3)-tert-butyl-4-hydroxyanisole (BHA) reduced intracellular H₂O₂ level (81.20±1.42 ng/egg) and protected against calcium ionophore-induced morphological changes characteristics of egg activation and apoptosis. These results clearly suggest that calcium ionophore-induced activation and apoptosis are associated with the generation of intracellular H₂O₂ in rat eggs.     

Synthesis,Antioxidant Activity,and Structure–Activity Relationship of SCAP1 Analogues

Nine analogues of antioxidant peptide SCAP1 were successfully synthesised using a solid-phase method on a 2-chlorotrytil resin. The compounds were obtained in a range of yields of 7.0–57.8%. The occurrence of aggregation during the synthesis is suspected to be responsible for the poor yields. All peptides were characterized by high-resolution time-of-flight mass spectrometry (HR-TOFMS) and nuclear magnetic resonance (NMR). The antioxidant activities of the SCAP1 analogues as well as SCAP1 were analysed utilising the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay. The results revealed that all of the analysed peptides exhibited moderate antioxidant properties. Moreover, the evaluation of the structure–activity relationship showed that the Asn residue is an important requirement for the antioxidant activity of SCAP1. The replacement of Asn with other amino acid residues (Thr, Pro, Tyr, Trp and Phe) resulted in a decrease in the IC₅₀ values of the peptides. Notably, however, the replacement of the Lys residue with Val marginally increased the activity.

     

Calcium ionophore-induced egg activation and apoptosis are associated with the generation of intracellular hydrogen peroxide

The present study was designed to investigate whether calcium ionophore-induced activation and apoptosis are associated with the generation of hydrogen peroxide (H(2)O(2)) in rat eggs cultured in vitro. Culture of metaphase-II (M-II) arrested eggs in Ca(2+)/Mg(2+)-deficient medium did not induce egg activation, while a second polar body was observed in 20% of eggs when cultured in Ca(2+)/Mg(2+)-supplemented medium. In Ca(2+)/Mg(2+)-deficient medium, lower concentrations of calcium ionophore (0.2,0.4 and 0.8 microm) not only induced egg activation in a dose-dependent manner but also generation of intracellular H(2)O(2) (84.40+/-0.50 ng/egg) when compared to control eggs (80.46+/-1.34 ng/egg). The higher concentration of calcium ionophore (1.6 microm) induced apoptosis and pronounced generation of intracellular H(2)O(2) (92.43+/-0.93 ng/egg) in treated eggs. Conversely, cell-permeant antioxidant such as 2(3)-tert-butyl-4-hydroxyanisole (BHA) reduced intracellular H(2)O(2) level (81.20+/-1.42 ng/egg) and protected against calcium ionophore-induced morphological changes characteristics of egg activation and apoptosis. These results clearly suggest that calcium ionophore-induced activation and apoptosis are associated with the generation of intracellular H(2)O(2) in rat eggs.     

Geographic distribution of livestock-associated Staphylococcus aureus in the United States

Sampling for livestock-associated Staphylococcus aureus (LA-SA) in the United States is haphazard. The diversity of LA-S. aureus in the U.S. appears to be greater than in other countries. We review the epidemiology of LA-S. aureus in U.S. pigs, occupationally-exposed individuals, and environmental samples to assess the diversity and abundance of U.S. LA-S. aureus.